The object of the invention is a suspension smelting furnace and a concentrate burner. A further object of the invention is the method of using the suspension smelting furnace.
The invention also relates to various uses of the method, the suspension smelting furnace, and the concentrate burner for solving process problems of different types of the suspension smelting furnace and/or improving the process effectiveness.
The invention relates to the method that takes place in the suspension smelting furnace, such as a flash smelting furnace, and to the suspension smelting furnace, such as the flash smelting furnace.
The flash smelting furnace comprises three main parts: a reaction shaft, a lower furnace and a raised shaft. In the flash smelting process, a powdery solid matter, which comprises a sulphidic concentrate, a slag forming agent and other powdery components, is mixed with reaction gas by means of a concentrate burner in the upper part of the reaction shaft. The reaction gas can be air, oxygen or oxygen-enriched air. The concentrate burner comprises a feeder pipe for feeding the fine-grained solid matter into the reaction shaft, where the mouth of the feeder pipe opens in the reaction shaft. The concentrate burner further comprises a diffusion device, which is arranged concentrically inside the feeder pipe and which extends to a distance from the mouth of the feeder pipe inside the reaction shaft, and which comprises diffusion gas holes for directing a diffusion gas to the fine solid matter that flows around the diffusion device. The concentrate burner further comprises a gas supply device for feeding the reaction gas into the reaction shaft, the gas supply device opening in the reaction shaft through an annular discharge opening that surrounds the feeder pipe concentrically for mixing the reaction gas that discharges from the said annular discharge opening with the fine solid matter, which discharges from the feeder pipe in the middle and which is directed sidewards by means of the diffusion gas.
The flash smelting method comprises a stage at which, into the reaction shaft, fine solid matter is fed into the reaction shaft through the mouth of the feeder pipe of the concentrate burner. The flash smelting method further comprises a stage, at which diffusion gas is fed into the reaction shaft through the diffusion gas holes of the diffusion device of the concentrate burner for directing the diffusion gas to the fine solid matter that flows around the diffusion device, and a stage, at which the reaction gas is fed into the reaction shaft through the annular discharge opening of the gas supply device of the concentrate burner for mixing the reaction gas with the fine solid matter, which discharges from the feeder pipe in the middle and which is directed sidewards by means of the diffusion gas.
In most cases, the energy needed for the smelting is obtained from the mixture itself, when the components of the mixture, which are fed into the reaction shaft, the powdery solid matter and the reaction gas, react with each other. However, there are raw materials which, when reacting with each other, do not produce enough energy and the sufficient smelting of which requires that a fuel gas is also fed into the reaction shaft to produce energy for the smelting.
Publication U.S. Pat. No. 5,362,032 presents a concentrate burner.